1. Field
Embodiments of the present invention relate to a battery unit which can be mounted in an electronic apparatus such as a portable computer.
2. Description of the Related Art
A portable computer has a battery unit as a power source. A battery unit has cells and a case to contain the cells. The case is formed to be rectangular with a predetermined thickness.
Such a battery unit is placed in a housing of a portable computer together with an expansion unit such as a CD-ROM drive. The expansion unit has a thin wall portion decreased in thickness on one side. The thin wall portion adjoins to the battery unit in the housing.
A battery unit for a portable computer has been demanded to offer increased capacity to meet the advanced functions of a portable computer. As a means to increase the battery capacity, a conventional battery unit has an extended portion extending toward an expansion unit at the end portion of a case. The conventional battery unit contains a substrate in the extended portion. The substrate is electrically connected to cells. By housing the substrate in the extended portion, most space in the case can be used to accommodate the cells.
The extended portion of the battery unit is formed by cutting off the end portion of the case adjacent to the thin wall portion of the expansion unit. The extended portion of the battery unit and the thin wall portion of the expansion unit are laid in the direction of the thickness of the housing. For example, Jpn. Pat. Appln. KOKAI Publication No. 2001-143673 discloses an electronic apparatus provided with such a battery unit.
A portable computer has been demanded to be slimmer to increase portability. However, in a conventional portable computer, the thin wall portion of an expansion unit is laid on the extended portion of a battery unit. Thus, in a battery unit having an extended portion, the space in a housing can be effectively used, but the thickness of the housing cannot be decreased.